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第07講函數(shù)的圖象(精講+精練)目錄第一部分:知識(shí)點(diǎn)精準(zhǔn)記憶第二部分:課前自我評(píng)估測(cè)試第三部分:典型例題剖析高頻考點(diǎn)一:畫出函數(shù)的圖象高頻考點(diǎn)二:函數(shù)圖象的識(shí)別高頻考點(diǎn)三:函數(shù)圖象的應(yīng)用①研究函數(shù)的性質(zhì)②確定零點(diǎn)個(gè)數(shù)③解不等式④求參數(shù)的取值范圍第四部分:高考真題感悟第五部分:第07講函數(shù)的圖象(精練)第一部分:知識(shí)點(diǎn)精準(zhǔn)記憶第一部分:知識(shí)點(diǎn)精準(zhǔn)記憶1、平移變換(左“+”右“-”;上“+”下“-”)①SKIPIF1<0②SKIPIF1<0③SKIPIF1<0④SKIPIF1<0注:左右平移只能單獨(dú)一個(gè)SKIPIF1<0加或者減,注意當(dāng)SKIPIF1<0前系數(shù)不為1,需將系數(shù)提取到外面.2、對(duì)稱變換①SKIPIF1<0的圖象SKIPIF1<0SKIPIF1<0的圖象;②SKIPIF1<0的圖象SKIPIF1<0SKIPIF1<0的圖象;③SKIPIF1<0的圖象SKIPIF1<0SKIPIF1<0的圖象;④SKIPIF1<0(SKIPIF1<0,且SKIPIF1<0)的圖象SKIPIF1<0SKIPIF1<0(SKIPIF1<0,且SKIPIF1<0)的圖象.3、伸縮變換①SKIPIF1<0SKIPIF1<0SKIPIF1<0.②SKIPIF1<0SKIPIF1<0SKIPIF1<0.4、翻折變換(絕對(duì)值變換)①SKIPIF1<0的圖象SKIPIF1<0SKIPIF1<0的圖象;(口訣;以SKIPIF1<0軸為界,保留SKIPIF1<0軸上方的圖象;將SKIPIF1<0軸下方的圖象翻折到SKIPIF1<0軸上方)②SKIPIF1<0的圖象SKIPIF1<0SKIPIF1<0的圖象.(口訣;以SKIPIF1<0軸為界,去掉SKIPIF1<0軸左側(cè)的圖象,保留SKIPIF1<0軸右側(cè)的圖象;將SKIPIF1<0軸右側(cè)圖象翻折到SKIPIF1<0軸左側(cè);本質(zhì)是個(gè)偶函數(shù))5、圖象識(shí)別技巧(按使用頻率優(yōu)先級(jí)排序)①特殊值法(觀察圖象,尋找圖象中出現(xiàn)的特殊值)②單調(diào)性法(SKIPIF1<0;SKIPIF1<0;SKIPIF1<0,SKIPIF1<0;通過(guò)求導(dǎo)判斷單調(diào)性)③奇偶性法SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0偶函數(shù)偶函數(shù)偶函數(shù)偶函數(shù)偶函數(shù)偶函數(shù)偶函數(shù)奇函數(shù)不能確定不能確定奇函數(shù)奇函數(shù)奇函數(shù)偶函數(shù)不能確定不能確定奇函數(shù)奇函數(shù)奇函數(shù)奇函數(shù)奇函數(shù)奇函數(shù)偶函數(shù)偶函數(shù)④極限(左右極限)(SKIPIF1<0;SKIPIF1<0;SKIPIF1<0;SKIPIF1<0;)⑤零點(diǎn)法⑥極大值極小值法第二部分:課前自我評(píng)估測(cè)試第二部分:課前自我評(píng)估測(cè)試1.(2022·陜西西安·高一期末)函數(shù)SKIPIF1<0的圖像大致為(

)A. B.C. D.【答案】CSKIPIF1<0的定義域?yàn)镾KIPIF1<0,SKIPIF1<0,所以SKIPIF1<0是奇函數(shù),圖象關(guān)于原點(diǎn)對(duì)稱,所以AD選項(xiàng)錯(cuò)誤.SKIPIF1<0,所以B選項(xiàng)錯(cuò)誤.故選:C2.(2022·北京·高三學(xué)業(yè)考試)函數(shù)SKIPIF1<0的圖象如圖所示,則不等式SKIPIF1<0的解集為(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】C由圖象可知,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0.故選:C3.(2022·全國(guó)·高三專題練習(xí))在同一直角坐標(biāo)系中,函數(shù)SKIPIF1<0,SKIPIF1<0的圖象可能是(

)A. B.C. D.【答案】DA:沒(méi)有冪函數(shù)圖象,不符合;B:SKIPIF1<0中SKIPIF1<0,SKIPIF1<0中SKIPIF1<0,不符合;C:SKIPIF1<0中SKIPIF1<0,SKIPIF1<0中SKIPIF1<0,不符合;D:SKIPIF1<0中SKIPIF1<0,SKIPIF1<0中SKIPIF1<0,符合.故選:D.4.(2022·浙江金華第一中學(xué)高一期末)圖(1)是某條公共汽車線路收支差額SKIPIF1<0關(guān)于乘客量SKIPIF1<0的圖象,圖(2)?(3)是由于目前本條路線虧損,公司有關(guān)人員提出的兩種扭虧為盈的建議,則下列說(shuō)法錯(cuò)誤的是(

)A.圖(1)的點(diǎn)SKIPIF1<0的實(shí)際意義為:當(dāng)乘客量為0時(shí),虧損1個(gè)單位B.圖(1)的射線SKIPIF1<0上的點(diǎn)表示當(dāng)乘客量小于3時(shí)將虧損,大于3時(shí)將盈利C.圖(2)的建議為降低成本而保持票價(jià)不變D.圖(3)的建議為降低成本的同時(shí)提高票價(jià)【答案】DA:當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,所以當(dāng)乘客量為0時(shí),虧損1個(gè)單位,故本選項(xiàng)說(shuō)法正確;B:當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,所以本選項(xiàng)說(shuō)法正確;C:降低成本而保持票價(jià)不變,兩條線是平行,所以本選項(xiàng)正確;D:由圖可知中:成本不變,同時(shí)提高票價(jià),所以本選項(xiàng)說(shuō)法不正確,故選:D第三部分:典型例題剖析第三部分:典型例題剖析高頻考點(diǎn)一:畫出函數(shù)的圖象1.(2021·寧夏·銀川市第六中學(xué)高一期中)已知函數(shù)SKIPIF1<0.(1)證明SKIPIF1<0是偶函數(shù);(2)畫出這個(gè)函數(shù)的圖象;(3)求函數(shù)SKIPIF1<0的值域.【答案】(1)證明見解析;(2)圖象見解析;(3)SKIPIF1<0(1)解:由題知函數(shù)的定義域關(guān)于原點(diǎn)對(duì)稱,SKIPIF1<0,所以函數(shù)SKIPIF1<0是偶函數(shù)SKIPIF1<0(2)解:由題知SKIPIF1<0,進(jìn)而結(jié)合二次函數(shù)與分段函數(shù)的性質(zhì)作圖如下:(3)解:由(2)的函數(shù)圖象可知函數(shù)的最小值為SKIPIF1<0,函數(shù)的最大值為SKIPIF1<0,所以函數(shù)SKIPIF1<0的值域?yàn)镾KIPIF1<02.(2021·山東臨沂·高一期中)已知SKIPIF1<0是整數(shù),冪函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞增.(1)求SKIPIF1<0的解析式;(2)若SKIPIF1<0,畫出函數(shù)SKIPIF1<0的大致圖象;(3)寫出SKIPIF1<0的單調(diào)區(qū)間,并用定義法證明SKIPIF1<0在區(qū)間SKIPIF1<0上的單調(diào)性.【答案】(1)SKIPIF1<0(2)作圖見解析(3)單調(diào)減區(qū)間為SKIPIF1<0,SKIPIF1<0,單調(diào)增區(qū)間為SKIPIF1<0,SKIPIF1<0,證明見解析(1)解:由題意可知,SKIPIF1<0,即SKIPIF1<0,因?yàn)镾KIPIF1<0是整數(shù),所以SKIPIF1<0,或SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,綜上可知,SKIPIF1<0的解析式為SKIPIF1<0;(2)解:由(1)知SKIPIF1<0,則SKIPIF1<0,函數(shù)SKIPIF1<0的圖象如圖所示,(3)解:由(2)可知,SKIPIF1<0的單調(diào)減區(qū)間為SKIPIF1<0,SKIPIF1<0,單調(diào)增區(qū)間為SKIPIF1<0,SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,設(shè)任意的SKIPIF1<0,且SKIPIF1<0,則SKIPIF1<0,∵SKIPIF1<0,且SKIPIF1<0,∴SKIPIF1<0,SKIPIF1<0,∴SKIPIF1<0,即SKIPIF1<0,所以SKIPIF1<0在區(qū)間SKIPIF1<0上單調(diào)遞增.3.(2021·全國(guó)·高一課時(shí)練習(xí))根據(jù)SKIPIF1<0的圖像,作出下列函數(shù)的圖像:(1)SKIPIF1<0;(2)SKIPIF1<0;(3)SKIPIF1<0;(4)SKIPIF1<0.(1)作出函數(shù)SKIPIF1<0關(guān)于縱軸對(duì)稱的圖像,連同函數(shù)SKIPIF1<0的圖像,就是該函數(shù)的圖像,如下圖所示:(2)把函數(shù)SKIPIF1<0的圖像中縱軸下面的部分,做關(guān)于橫軸對(duì)稱,擦掉縱軸下面的部分,函數(shù)圖像如下圖所示:(3)作出函數(shù)SKIPIF1<0關(guān)于縱軸對(duì)稱的圖像,連同函數(shù)SKIPIF1<0的圖像一起向右平移一個(gè)單位即可,如下圖所示:(4)把函數(shù)SKIPIF1<0的圖像中縱軸下面的部分,做關(guān)于橫軸對(duì)稱,擦掉縱軸下面的部分,然后再向右平移一個(gè)單位,如下圖所示:高頻考點(diǎn)二:函數(shù)圖象的識(shí)別1.(2022·福建福州·高一期末)已知函數(shù)SKIPIF1<0,則SKIPIF1<0的大致圖像為(

)A. B.C. D.【答案】B解:由題得SKIPIF1<0,所以排除選項(xiàng)A,D.SKIPIF1<0,所以排除選項(xiàng)C.故選:B2.(2022·湖南·株洲二中高一階段練習(xí))函數(shù)SKIPIF1<0的圖象大致為(

)A. B.C. D.【答案】D由題意知,SKIPIF1<0,解得SKIPIF1<0,所以SKIPIF1<0定義域SKIPIF1<0關(guān)于原點(diǎn)對(duì)稱,又因?yàn)镾KIPIF1<0,所以此函數(shù)為奇函數(shù),圖像關(guān)于原點(diǎn)對(duì)稱,排除A.當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,排除B.SKIPIF1<0,函數(shù)只有1個(gè)零點(diǎn),排除C.故選:D3.(2022·山東德州·高三期末)已知函數(shù)SKIPIF1<0,則函數(shù)SKIPIF1<0的大致圖象為(

)A. B.C. D.【答案】D由題可知:函數(shù)定義域?yàn)镾KIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,故該函數(shù)為奇函數(shù),排除A,C又SKIPIF1<0,所以排除B,故選:D4.(2022·浙江·高三學(xué)業(yè)考試)函數(shù)SKIPIF1<0的圖象大致為(

)A. B.C. D.【答案】B因?yàn)楹瘮?shù)SKIPIF1<0的定義域?yàn)镽,且SKIPIF1<0不是偶函數(shù),所以排除C、D;又SKIPIF1<0,排除A,即確定答案為B.故選:B.5.(2022·全國(guó)·高三專題練習(xí)(文))函數(shù)SKIPIF1<0的部分圖象大致是(

)A. B.C. D.【答案】A由題可知函數(shù)定義域?yàn)镾KIPIF1<0,則SKIPIF1<0,又SKIPIF1<0所以SKIPIF1<0是奇函數(shù),且SKIPIF1<0時(shí),SKIPIF1<0,故選項(xiàng)A正確.

故選:A6.(2022·廣西南寧·一模(文))函數(shù)SKIPIF1<0的圖象最有可能是以下的(

)A. B.C. D.【答案】BSKIPIF1<0定義域?yàn)镾KIPIF1<0,關(guān)于原點(diǎn)對(duì)稱,又SKIPIF1<0,所以SKIPIF1<0是奇函數(shù),故排除CD,又SKIPIF1<0,故排除A選項(xiàng),B正確.故選:B7.(2022·陜西咸陽(yáng)·高一期末)函數(shù)SKIPIF1<0的大致圖像為(

)A. B.C. D.【答案】D對(duì)任意的SKIPIF1<0,SKIPIF1<0,則函數(shù)SKIPIF1<0的定義域?yàn)镾KIPIF1<0,排除C選項(xiàng);SKIPIF1<0,SKIPIF1<0,所以,函數(shù)SKIPIF1<0為偶函數(shù),排除B選項(xiàng),因?yàn)镾KIPIF1<0,排除A選項(xiàng).故選:D.高頻考點(diǎn)三:函數(shù)圖象的應(yīng)用①研究函數(shù)的性質(zhì)1.(2022·河南·林州一中高一開學(xué)考試)已知函數(shù)SKIPIF1<0,SKIPIF1<0則(

)A.SKIPIF1<0的最大值為3,最小值為1B.SKIPIF1<0的最大值為SKIPIF1<0,無(wú)最小值C.SKIPIF1<0的最大值為SKIPIF1<0,最小值為1D.SKIPIF1<0的最大值為3,最小值為-1【答案】B解:SKIPIF1<0,由SKIPIF1<0與SKIPIF1<0,解SKIPIF1<0得SKIPIF1<0;解SKIPIF1<0得SKIPIF1<0;所以SKIPIF1<0與SKIPIF1<0的交點(diǎn)坐標(biāo)為SKIPIF1<0,SKIPIF1<0,因?yàn)镾KIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0的圖象如下圖所示:由圖象,可知最大值為SKIPIF1<0,無(wú)最小值,故選:B.2.(2022·全國(guó)·高一期末)已知函數(shù)SKIPIF1<0.(1)判斷函數(shù)SKIPIF1<0的奇偶性,并證明;(2)畫出函數(shù)SKIPIF1<0的圖象,并討論方程SKIPIF1<0的解的個(gè)數(shù).【答案】(1)函數(shù)SKIPIF1<0為偶函數(shù),證明見解析;(2)圖象見解析;當(dāng)SKIPIF1<0時(shí),方程的解為0個(gè);當(dāng)SKIPIF1<0或SKIPIF1<0時(shí),方程的解為2個(gè);當(dāng)SKIPIF1<0時(shí),方程的解為4個(gè);當(dāng)SKIPIF1<0時(shí),方程的解為3個(gè).(1)函數(shù)SKIPIF1<0為偶函數(shù),∵SKIPIF1<0,∴SKIPIF1<0的定義域?yàn)镽,關(guān)于原點(diǎn)對(duì)稱,且SKIPIF1<0,所以SKIPIF1<0為偶函數(shù);(2)因?yàn)镾KIPIF1<0,所以函數(shù)SKIPIF1<0的圖象如下所示:方程SKIPIF1<0的解的個(gè)數(shù),即SKIPIF1<0與SKIPIF1<0的交點(diǎn)個(gè)數(shù),結(jié)合函數(shù)圖象可知:當(dāng)SKIPIF1<0時(shí),有0個(gè)解,當(dāng)SKIPIF1<0或SKIPIF1<0時(shí),有2個(gè)解,當(dāng)SKIPIF1<0時(shí),有4個(gè)解,當(dāng)SKIPIF1<0時(shí),有3個(gè)解.3.(2022·山東濰坊·高一期末)已知定義在SKIPIF1<0上的奇函數(shù)SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0.(1)求函數(shù)SKIPIF1<0在SKIPIF1<0上的解析式;(2)在給出的直角坐標(biāo)系中作出SKIPIF1<0的圖像,并寫出函數(shù)SKIPIF1<0的單調(diào)區(qū)間.【答案】(1)SKIPIF1<0(2)圖像答案見解析,單調(diào)遞增區(qū)間為SKIPIF1<0,單調(diào)遞減區(qū)間為SKIPIF1<0(1)設(shè)SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0,又SKIPIF1<0為奇函數(shù),所以SKIPIF1<0,又SKIPIF1<0為定義在SKIPIF1<0上的奇函數(shù),所以SKIPIF1<0,所以SKIPIF1<0(2)作出函數(shù)SKIPIF1<0的圖像,如圖所示:函數(shù)SKIPIF1<0的單調(diào)遞增區(qū)間為SKIPIF1<0,單調(diào)遞減區(qū)間為SKIPIF1<0.②確定零點(diǎn)個(gè)數(shù)1.(2022·全國(guó)·高三階段練習(xí))函數(shù)SKIPIF1<0的零點(diǎn)個(gè)數(shù)為(

).A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】D令SKIPIF1<0,得SKIPIF1<0;在同一直角坐標(biāo)系中分別作出SKIPIF1<0,SKIPIF1<0的大致圖象如圖所示;觀察可知,兩個(gè)函數(shù)的圖象有SKIPIF1<0個(gè)交點(diǎn)(其中SKIPIF1<0個(gè)交點(diǎn)的橫坐標(biāo)介于SKIPIF1<0到SKIPIF1<0之間,另外兩個(gè)交點(diǎn)分別為SKIPIF1<0,SKIPIF1<0,故函數(shù)SKIPIF1<0的零點(diǎn)個(gè)數(shù)為SKIPIF1<0,故選:D.2.(2022·江西·高一期末)已知函數(shù)SKIPIF1<0,若方程SKIPIF1<0恰有兩個(gè)不等的實(shí)根,則實(shí)數(shù)SKIPIF1<0的取值范圍是(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】B方程SKIPIF1<0恰有兩個(gè)不等的實(shí)根,等價(jià)于SKIPIF1<0與SKIPIF1<0的圖象有兩個(gè)交點(diǎn),SKIPIF1<0的圖象如圖所示,平移水平直線SKIPIF1<0可得SKIPIF1<0,故選:B.3.(2022·湖南·長(zhǎng)沙市南雅中學(xué)高三階段練習(xí))函數(shù)SKIPIF1<0有三個(gè)不同的零點(diǎn),則實(shí)數(shù)t的范圍是__________.【答案】SKIPIF1<0作出函數(shù)SKIPIF1<0的圖象和直線SKIPIF1<0,如圖,由圖象可得SKIPIF1<0時(shí),直線與函數(shù)圖象有三個(gè)交點(diǎn),即函數(shù)SKIPIF1<0有三個(gè)零點(diǎn).SKIPIF1<0.故答案為:SKIPIF1<0.4.(2022·湖南·高一課時(shí)練習(xí))用圖象法判定方程SKIPIF1<0的根的個(gè)數(shù).【答案】1方程SKIPIF1<0根的個(gè)數(shù),等價(jià)于函數(shù)SKIPIF1<0與SKIPIF1<0圖象的交點(diǎn)個(gè)數(shù),函數(shù)SKIPIF1<0與SKIPIF1<0在同一坐標(biāo)系中的圖象如圖所示,兩函數(shù)圖象只有一個(gè)交點(diǎn),所以方程SKIPIF1<0的根的個(gè)數(shù)為1③解不等式1.(2022·全國(guó)·池州市第一中學(xué)高一開學(xué)考試)已知函數(shù)SKIPIF1<0的圖象如圖,則不等式SKIPIF1<0的解集為(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】D不等式SKIPIF1<0,則SKIPIF1<0或SKIPIF1<0,觀察圖象,解SKIPIF1<0得SKIPIF1<0,解SKIPIF1<0得SKIPIF1<0,所以不等式SKIPIF1<0的解集為SKIPIF1<0.故選:D2.(2022·河北·高三階段練習(xí))已知函數(shù)SKIPIF1<0,則SKIPIF1<0的解集為(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】C作出函數(shù)SKIPIF1<0與SKIPIF1<0的圖象,如圖,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,作出函數(shù)SKIPIF1<0與SKIPIF1<0的圖象,由圖象可知,此時(shí)解得SKIPIF1<0;當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,作出函數(shù)SKIPIF1<0與SKIPIF1<0的圖象,它們的交點(diǎn)坐標(biāo)為SKIPIF1<0、SKIPIF1<0,結(jié)合圖象知此時(shí)SKIPIF1<0.所以不等式SKIPIF1<0的解集為SKIPIF1<0SKIPIF1<0.故選:C3.(2022·北京·模擬預(yù)測(cè))已知函數(shù)SKIPIF1<0,則不等式SKIPIF1<0的解集是(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B不等式SKIPIF1<0,分別畫出函數(shù)SKIPIF1<0和SKIPIF1<0的圖象,由圖象可知SKIPIF1<0和SKIPIF1<0有兩個(gè)交點(diǎn),分別是SKIPIF1<0和SKIPIF1<0,由圖象可知SKIPIF1<0的解集是SKIPIF1<0即不等式SKIPIF1<0的解集是SKIPIF1<0.故選:B4.(2022·河南·信陽(yáng)高中高一階段練習(xí)(理))已知定義在R上的函數(shù)SKIPIF1<0滿足SKIPIF1<0,且當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,若對(duì)任SKIPIF1<0都有SKIPIF1<0,則m的取值范圍是_________.【答案】SKIPIF1<0,SKIPIF1<0.解:因?yàn)镾KIPIF1<0滿足SKIPIF1<0,即SKIPIF1<0;又由SKIPIF1<0,可得SKIPIF1<0,畫出當(dāng)SKIPIF1<0,SKIPIF1<0時(shí),SKIPIF1<0的圖象,將SKIPIF1<0在SKIPIF1<0,SKIPIF1<0的圖象向右平移SKIPIF1<0個(gè)單位(橫坐標(biāo)不變,縱坐標(biāo)變?yōu)樵瓉?lái)的2倍),再向左平移SKIPIF1<0個(gè)單位(橫坐標(biāo)不變,縱坐標(biāo)變?yōu)樵瓉?lái)的SKIPIF1<0倍),由此得到函數(shù)SKIPIF1<0的圖象如圖:當(dāng)SKIPIF1<0,SKIPIF1<0時(shí),SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,又SKIPIF1<0,所以SKIPIF1<0,令SKIPIF1<0,由圖像可得SKIPIF1<0,則SKIPIF1<0,解得SKIPIF1<0,所以當(dāng)SKIPIF1<0時(shí),滿足對(duì)任意的SKIPIF1<0,SKIPIF1<0,都有SKIPIF1<0,故SKIPIF1<0的范圍為SKIPIF1<0,SKIPIF1<0.故答案為:SKIPIF1<0,SKIPIF1<0.④求參數(shù)的取值范圍1.(2022·山西·靈丘縣第一中學(xué)校高二階段練習(xí))已知函數(shù)SKIPIF1<0若直線SKIPIF1<0與SKIPIF1<0有三個(gè)不同的交點(diǎn),則實(shí)數(shù)SKIPIF1<0的取值范圍是(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】C設(shè)SKIPIF1<0與SKIPIF1<0相切于點(diǎn)SKIPIF1<0,則SKIPIF1<0,解得SKIPIF1<0,此時(shí)SKIPIF1<0,由SKIPIF1<0得SKIPIF1<0,由SKIPIF1<0可得SKIPIF1<0,此時(shí)切點(diǎn)為SKIPIF1<0,作出函數(shù)SKIPIF1<0與SKIPIF1<0的圖象如圖,由圖象可知,當(dāng)SKIPIF1<0或SKIPIF1<0時(shí),直線SKIPIF1<0與SKIPIF1<0有三個(gè)不同的交點(diǎn),故選:C2.(2022·河北石家莊·高一期末)已知函數(shù)SKIPIF1<0,若存在不相等的實(shí)數(shù)a,b,c,d滿足SKIPIF1<0,則SKIPIF1<0的取值范圍為(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】C由題設(shè),將問(wèn)題轉(zhuǎn)化為SKIPIF1<0與SKIPIF1<0的圖象有四個(gè)交點(diǎn),SKIPIF1<0,則在SKIPIF1<0上遞減且值域?yàn)镾KIPIF1<0;在SKIPIF1<0上遞增且值域?yàn)镾KIPIF1<0;在SKIPIF1<0上遞減且值域?yàn)镾KIPIF1<0,在SKIPIF1<0上遞增且值域?yàn)镾KIPIF1<0;SKIPIF1<0的圖象如下:所以SKIPIF1<0時(shí),SKIPIF1<0與SKIPIF1<0的圖象有四個(gè)交點(diǎn),不妨假設(shè)SKIPIF1<0,由圖及函數(shù)性質(zhì)知:SKIPIF1<0,易知:SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0.故選:C3.(多選)(2022·湖北·石首市第一中學(xué)高一階段練習(xí))函數(shù)SKIPIF1<0恰有2個(gè)零點(diǎn),則SKIPIF1<0的取值可以是(

)A.1 B.2 C.SKIPIF1<0 D.SKIPIF1<0【答案】BD解:由題意得:當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,該函數(shù)是由SKIPIF1<0向上或向下平移SKIPIF1<0個(gè)單位得到當(dāng)SKIPIF1<0時(shí),SKIPIF1<0對(duì)于函數(shù)SKIPIF1<0,令SKIPIF1<0,則SKIPIF1<0若SKIPIF1<0,即SKIPIF1<0,函數(shù)SKIPIF1<0與SKIPIF1<0軸沒(méi)有交點(diǎn),則SKIPIF1<0滿足不等式組SKIPIF1<0故可取SKIPIF1<0,如圖1所示;若SKIPIF1<0,即SKIPIF1<0,函數(shù)SKIPIF1<0與SKIPIF1<0軸有一個(gè)交點(diǎn),則SKIPIF1<0滿足不等式SKIPIF1<0或SKIPIF1<0,解得SKIPIF1<0或SKIPIF1<0或無(wú)解,如圖2所示;又SKIPIF1<0,解得SKIPIF1<0,故可取SKIPIF1<0故選:BD4.(2022·河南·欒川縣第一高級(jí)中學(xué)高二階段練習(xí)(理))已知函數(shù)SKIPIF1<0若SKIPIF1<0且SKIPIF1<0,則SKIPIF1<0的最小值是________.【答案】SKIPIF1<0##SKIPIF1<0函數(shù)SKIPIF1<0的圖象如圖所示.令SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0.令SKIPIF1<0,SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,SKIPIF1<0單調(diào)遞減,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,SKIPIF1<0單調(diào)遞增,所以SKIPIF1<0.故答案為:SKIPIF1<0.5.(2022·山西臨汾·二模(理))已知函數(shù)SKIPIF1<0有2個(gè)不同的零點(diǎn),則k的取值范圍是____________.【答案】SKIPIF1<0因?yàn)楹瘮?shù)SKIPIF1<0有2個(gè)不同的零點(diǎn),所以關(guān)于SKIPIF1<0的方程SKIPIF1<0在區(qū)間SKIPIF1<0內(nèi)有兩個(gè)不等的實(shí)根,即曲線SKIPIF1<0(圓SKIPIF1<0的上半部分)與經(jīng)過(guò)定點(diǎn)SKIPIF1<0的直線SKIPIF1<0有兩個(gè)不同的交點(diǎn),如圖過(guò)SKIPIF1<0作圓SKIPIF1<0的切線SKIPIF1<0,則點(diǎn)SKIPIF1<0到切線SKIPIF1<0的距離SKIPIF1<0,解得SKIPIF1<0(舍去)或SKIPIF1<0,所以SKIPIF1<0,得SKIPIF1<0,即k的取值范圍是SKIPIF1<0,故答案為:SKIPIF1<0第四部分:高考真題感悟第四部分:高考真題感悟1.(2021·天津·高考真題)函數(shù)SKIPIF1<0的圖像大致為(

)A. B.C. D.【答案】B設(shè)SKIPIF1<0,則函數(shù)SKIPIF1<0的定義域?yàn)镾KIPIF1<0,關(guān)于原點(diǎn)對(duì)稱,又SKIPIF1<0,所以函數(shù)SKIPIF1<0為偶函數(shù),排除AC;當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,所以SKIPIF1<0,排除D.故選:B.2.(2021·浙江·高考真題)已知函數(shù)SKIPIF1<0,則圖象為如圖的函數(shù)可能是(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】D對(duì)于A,SKIPIF1<0,該函數(shù)為非奇非偶函數(shù),與函數(shù)圖象不符,排除A;對(duì)于B,SKIPIF1<0,該函數(shù)為非奇非偶函數(shù),與函數(shù)圖象不符,排除B;對(duì)于C,SKIPIF1<0,則SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,與圖象不符,排除C.故選:D.3.(2020·天津·高考真題)函數(shù)SKIPIF1<0的圖象大致為(

)A. B.C. D.【答案】A由函數(shù)的解析式可得:SKIPIF1<0,則函數(shù)SKIPIF1<0為奇函數(shù),其圖象關(guān)于坐標(biāo)原點(diǎn)對(duì)稱,選項(xiàng)CD錯(cuò)誤;當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,選項(xiàng)B錯(cuò)誤.故選:A.【點(diǎn)睛】函數(shù)圖象的識(shí)辨可從以下方面入手:(1)從函數(shù)的定義域,判斷圖象的左右位置;從函數(shù)的值域,判斷圖象的上下位置.(2)從函數(shù)的單調(diào)性,判斷圖象的變化趨勢(shì).(3)從函數(shù)的奇偶性,判斷圖象的對(duì)稱性.(4)從函數(shù)的特征點(diǎn),排除不合要求的圖象.利用上述方法排除、篩選選項(xiàng).4.(2020·北京·高考真題)已知函數(shù)SKIPIF1<0,則不等式SKIPIF1<0的解集是(

).A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】D因?yàn)镾KIPIF1<0,所以SKIPIF1<0等價(jià)于SKIPIF1<0,在同一直角坐標(biāo)系中作出SKIPIF1<0和SKIPIF1<0的圖象如圖:兩函數(shù)圖象的交點(diǎn)坐標(biāo)為SKIPIF1<0,不等式SKIPIF1<0的解為SKIPIF1<0或SKIPIF1<0.所以不等式SKIPIF1<0的解集為:SKIPIF1<0.故選:D.5.(2020·浙江·高考真題)函數(shù)y=xcosx+sinx在區(qū)間[–π,π]的圖象大致為()A. B.C. D.【答案】A【詳解】因?yàn)镾KIPIF1<0,則SKIPIF1<0,即題中所給的函數(shù)為奇函數(shù),函數(shù)圖象關(guān)于坐標(biāo)原點(diǎn)對(duì)稱,據(jù)此可知選項(xiàng)CD錯(cuò)誤;且SKIPIF1<0時(shí),SKIPIF1<0,據(jù)此可知選項(xiàng)B錯(cuò)誤.故選:A.【點(diǎn)睛】函數(shù)圖象的識(shí)辨可從以下方面入手:(1)從函數(shù)的定義域,判斷圖象的左右位置;從函數(shù)的值域,判斷圖象的上下位置.(2)從函數(shù)的單調(diào)性,判斷圖象的變化趨勢(shì).(3)從函數(shù)的奇偶性,判斷圖象的對(duì)稱性.(4)從函數(shù)的特征點(diǎn),排除不合要求的圖象.利用上述方法排除、篩選選項(xiàng).6.(2021·湖南·高考真題)已知函數(shù)SKIPIF1<0(1)畫出函數(shù)SKIPIF1<0的圖象;(2)若SKIPIF1<0,求SKIPIF1<0的取值范圍.【答案】(1)答案見解析;(2)SKIPIF1<0(1)函數(shù)SKIPIF1<0的圖象如圖所示:(2)SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,可得:SKIPIF1<0,當(dāng)SKIPIF1<0,SKIPIF1<0,可得:SKIPIF1<0,所以SKIPIF1<0的解集為:SKIPIF1<0,所以SKIPIF1<0的取值范圍為SKIPIF1<0.第五部分:第07講函數(shù)的圖象(精練)第五部分:第07講函數(shù)的圖象(精練)一、單選題1.(2022·湖南·高一課時(shí)練習(xí))函數(shù)SKIPIF1<0與SKIPIF1<0的定義域均為SKIPIF1<0,它們的圖象如圖所示,則不等式SKIPIF1<0的解集是(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】A解:SKIPIF1<0即為函數(shù)SKIPIF1<0的圖像在函數(shù)SKIPIF1<0的圖像的上方的部分對(duì)應(yīng)自變量的范圍,由圖可知,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0或SKIPIF1<0,即不等式SKIPIF1<0的解集是SKIPIF1<0.故選:A.2.(2022·全國(guó)·高三專題練習(xí))如圖為函數(shù)SKIPIF1<0的圖象,則該函數(shù)可能為(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B由圖可知,SKIPIF1<0時(shí),SKIPIF1<0,ACD的函數(shù)SKIPIF1<0,故選:B.3.(2022·北京交通大學(xué)附屬中學(xué)高二階段練習(xí))函數(shù)SKIPIF1<0的圖象大致為(

)A.B.C. D.【答案】C根據(jù)題意,函數(shù)SKIPIF1<0,其定義域?yàn)镾KIPIF1<0,有SKIPIF1<0,即函數(shù)SKIPIF1<0為奇函數(shù),當(dāng)SKIPIF1<0時(shí),有SKIPIF1<0,函數(shù)的圖象在第一象限,分析選項(xiàng)可得:C符合故選:C【點(diǎn)睛】思路點(diǎn)睛:函數(shù)圖象的辨識(shí)可從以下方面入手:(1)從函數(shù)的定義域,判斷圖象的左右位置;從函數(shù)的值域,判斷圖象的上下位置.(2)從函數(shù)的單調(diào)性,判斷圖象的變化趨勢(shì);(3)從函數(shù)的奇偶性,判斷圖象的對(duì)稱性;(4)從函數(shù)的特征點(diǎn),排除不合要求的圖象.4.(2022·浙江紹興·模擬預(yù)測(cè))在同一直角坐標(biāo)系中,函數(shù)SKIPIF1<0,SKIPIF1<0,且SKIPIF1<0的圖象可能是(

)A. B.C. D.【答案】C解:因?yàn)楹瘮?shù)SKIPIF1<0的圖象與函數(shù)SKIPIF1<0的圖象關(guān)于SKIPIF1<0軸對(duì)稱,所以函數(shù)SKIPIF1<0的圖象恒過(guò)定點(diǎn)SKIPIF1<0,故選項(xiàng)A、B錯(cuò)誤;當(dāng)SKIPIF1<0時(shí),函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞增,所以函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減,又SKIPIF1<0在SKIPIF1<0和SKIPIF1<0上單調(diào)遞減,故選項(xiàng)D錯(cuò)誤,選項(xiàng)C正確.故選:C.5.(2022·新疆·模擬預(yù)測(cè)(理))我國(guó)著名數(shù)學(xué)家華羅庚曾說(shuō):“數(shù)缺形時(shí)少直觀,形缺數(shù)時(shí)難入微,數(shù)形結(jié)合百般好,隔裂分家萬(wàn)事休.”在數(shù)學(xué)的學(xué)習(xí)和研究中,常用函數(shù)的圖象來(lái)研究函數(shù)的性質(zhì),也常用函數(shù)的解析式來(lái)研究函數(shù)圖象的特征.我們從這個(gè)商標(biāo)中抽象出一個(gè)函數(shù)的圖象如圖,其對(duì)應(yīng)的函數(shù)解析式可能是(

)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】DA:函數(shù)的定義域?yàn)镾KIPIF1<0,不符合;B:由SKIPIF1<0,不符合;C:由SKIPIF1<0,不符合;D:SKIPIF1<0且定義域?yàn)镾KIPIF1<0,SKIPIF1<0為偶函數(shù),在SKIPIF1<0上SKIPIF1<0單調(diào)遞增,SKIPIF1<0上SKIPIF1<0單調(diào)遞減,結(jié)合偶函數(shù)的對(duì)稱性知:SKIPIF1<0上遞減,SKIPIF1<0上遞增,符合.故選:D6.(2022·四川達(dá)州·二模(理))函數(shù)SKIPIF1<0的部分圖象大致為(

)A. B.C. D.【答案】A∵函數(shù)SKIPIF1<0,SKIPIF1<0,∴SKIPIF1<0,故排除BD;又SKIPIF1<0,故排除C.故選:A.7.(2022·全國(guó)·高三專題練習(xí)(理))已知函數(shù)SKIPIF1<0,若SKIPIF1<0,SKIPIF1<0,SKIPIF1<0均不相等,且SKIPIF1<0=SKIPIF1<0=SKIPIF1<0,則SKIPIF1<0的取值范圍是(

)A.(1,10) B.(5,6) C.(10,12) D.(20,24)【答案】C畫出函數(shù)的圖象,如圖所示,不妨設(shè)SKIPIF1<0,因?yàn)镾KIPIF1<0,所以SKIPIF1<0,解得:SKIPIF1<0,SKIPIF1<0的取值范圍是SKIPIF1<0,所以SKIPIF1<0的取值范圍是SKIPIF1<0.故選:C8.(2022·貴州畢節(jié)·模擬預(yù)測(cè)(理))設(shè)SKIPIF1<0是定義在R上且周期為2的函數(shù),當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,其中a,SKIPIF1<0,且函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上恰有3個(gè)零點(diǎn),則a的取值不可能是(

)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.0【答案】D因?yàn)镾KIPIF1<0是定義在R上且周期為2的函數(shù),所以SKIPIF1<0,所以SKIPIF1<0,得SKIPIF1<0,則SKIPIF1<0時(shí),SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,其圖象如圖所示SKIPIF1<0,由于周期為2,所以SKIPIF1<0,所以SKIPIF1<0不符合題意,當(dāng)SKIPIF1<0時(shí),則圖象向上平移,函數(shù)無(wú)零點(diǎn),所以不符合,當(dāng)SKIPIF1<0時(shí),可得SKIPIF1<0在SKIPIF1<0上有一個(gè)零點(diǎn),所以SKIPIF1<0在SKIPIF1<0上有零點(diǎn),所以SKIPIF1<0在區(qū)間SKIPIF1<0上恰有3個(gè)零點(diǎn),符合題意,當(dāng)SKIPIF1<0時(shí),可得SKIPIF1<0在SKIPIF1<0上有2個(gè)零點(diǎn),由于函數(shù)的周期為2,所以SKIPIF1<0在SKIPIF1<0上有6個(gè)零點(diǎn),不符合題意,當(dāng)SKIPIF1<0時(shí),則可得SKIPIF1<0,在區(qū)間SKIPIF1<0上恰有3個(gè)零點(diǎn),所以符合題意,當(dāng)SKIPIF1<0時(shí),函數(shù)圖象與SKIPIF1<0軸無(wú)交點(diǎn),綜上,當(dāng)SKIPIF1<0或SKIPIF1<0時(shí),SKIPIF1<0在區(qū)間SKIPIF1<0上恰有3個(gè)零點(diǎn),故選:D二、填空題9.(2022·重慶·高一期末)已知冪函數(shù)SKIPIF1<0的圖象如圖所示,則SKIPIF1<0______.(寫出一個(gè)正確結(jié)果即可)【答案】SKIPIF1<0(答案不唯一)由冪函數(shù)圖象知,函數(shù)SKIPIF1<0的定義域是SKIPIF1<0,且在SKIPIF1<0單調(diào)遞減,于是得冪函數(shù)的冪指數(shù)為負(fù)數(shù),而函數(shù)SKIPIF1<0的圖象關(guān)于y軸對(duì)稱,即冪函數(shù)SKIPIF1<0是偶函數(shù),則冪函數(shù)SKIPIF1<0的冪指數(shù)為偶數(shù),綜上得:SKIPIF1<0.故答案為:SKIPIF1<010.(2022·山東威海·高一期末)已知函數(shù)SKIPIF1<0,若關(guān)于SKIPIF1<0的方程SKIPIF1<0有四個(gè)根,則實(shí)數(shù)SKIPIF1<0的取值范圍為______.【答案】SKIPIF1<0由SKIPIF1<0,得SKIPIF1<0令SKIPIF1<0,畫出圖像由圖可知,當(dāng)SKIPIF1<0時(shí),方程SKIPIF1<0有四解,即方程SKIPIF1<0有四個(gè)根.故答案為:SKIPIF1<011.(2022·云南·高三階段練習(xí)(理))函數(shù)SKIPIF1<0,函數(shù)SKIPIF1<0,若函數(shù)SKIPIF1<0恰有4個(gè)零點(diǎn),則實(shí)數(shù)m的取值范圍是_________.【答案】SKIPIF1<0由題意,函數(shù)SKIPIF1<0恰有4個(gè)零點(diǎn),即SKIPIF1<0,即SKIPIF1<0有4個(gè)不同的實(shí)數(shù)根,即直線SKIPIF1<0與函數(shù)SKIPIF1<0的圖象有四個(gè)不同的交點(diǎn),又由SKIPIF1<0,作出該函數(shù)SKIPIF1<0的圖象,如圖所示,當(dāng)SKIPIF1<0時(shí),函數(shù)SKIPIF1<0,其中SKIPIF1<0時(shí),SKIPIF1<0;當(dāng)SKIPIF1<0時(shí),函數(shù)SKIPIF1<0,其中SKIPIF1<0時(shí),SKIPIF1<0,結(jié)合圖象可得,當(dāng)SKIPIF1<0時(shí),直線SKIPIF1<0與函數(shù)SKIPIF1<0的圖象有4個(gè)不同的交點(diǎn),即函數(shù)SKIPIF1<0恰有4個(gè)零點(diǎn)時(shí),所以實(shí)數(shù)SKIPIF1<0的取值范圍是SKIPIF1<0.故答案為:SKIPIF1<0.12.(2022·重慶·高一期末)設(shè)SKIPIF1<0函數(shù)SKIPIF1<0,若關(guān)于SKIPIF1<0的方程SKIPIF1<0有三個(gè)不相等的實(shí)數(shù)解,則實(shí)數(shù)SKIPIF1<0的取值范圍是______.【答案】

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